diff --git a/c/containers/lrec.c b/c/containers/lrec.c
index 111cfcbad..548284556 100644
--- a/c/containers/lrec.c
+++ b/c/containers/lrec.c
@@ -154,6 +154,17 @@ char* lrec_get_pff(lrec_t* prec, char* key, char** ppfree_flags) {
 	}
 }
 
+char* lrec_get_ext(lrec_t* prec, char* key, lrece_t** ppentry) {
+	lrece_t* pe = lrec_find_entry(prec, key);
+	if (pe != NULL) {
+		*ppentry = pe;
+		return pe->value;
+	} else {
+		*ppentry = NULL;;
+		return NULL;
+	}
+}
+
 // ----------------------------------------------------------------
 void lrec_remove(lrec_t* prec, char* key) {
 	lrece_t* pe = lrec_find_entry(prec, key);
diff --git a/c/containers/lrec.h b/c/containers/lrec.h
index 8215a2288..f4a23b647 100644
--- a/c/containers/lrec.h
+++ b/c/containers/lrec.h
@@ -118,10 +118,16 @@ void  lrec_put(lrec_t* prec, char* key, char* value, char free_flags);
 void  lrec_prepend(lrec_t* prec, char* key, char* value, char free_flags);
 
 char* lrec_get(lrec_t* prec, char* key);
+
 // This returns a pointer to the lrec's free-flags so that the caller can do ownership-transfer
 // of about-to-be-removed key-value pairs.
 char* lrec_get_pff(lrec_t* prec, char* key, char** ppfree_flags);
 
+// This returns a pointer to the entry so the caller can update it directly without needing
+// to do another field-scan on subsequent lrec_put etc. This is a performance optimization;
+// it also allows mlr nest --explode to do explode-in-place rather than explode-at-end.
+char* lrec_get_ext(lrec_t* prec, char* key, lrece_t** ppentry);
+
 void  lrec_remove(lrec_t* prec, char* key);
 void  lrec_rename(lrec_t* prec, char* old_key, char* new_key, int new_needs_freeing);
 void  lrec_move_to_head(lrec_t* prec, char* key);
diff --git a/c/mapping/mapper_nest.c b/c/mapping/mapper_nest.c
index e59398a78..3b1930d5f 100644
--- a/c/mapping/mapper_nest.c
+++ b/c/mapping/mapper_nest.c
@@ -237,10 +237,8 @@ static sllv_t* mapper_nest_explode_values_across_fields(lrec_t* pinrec, context_
 		return sllv_single(NULL);
 	mapper_nest_state_t* pstate = (mapper_nest_state_t*)pvstate;
 
-	// xxx get_ext w/ lrece_t*
-	// xxx insert after
-	// xxx unlink
-	char* field_value = lrec_get(pinrec, pstate->field_name);
+	lrece_t* pentry = NULL;
+	char* field_value = lrec_get_ext(pinrec, pstate->field_name, &pentry);
 	if (field_value == NULL) {
 		return sllv_single(pinrec);
 	}
@@ -254,8 +252,9 @@ static sllv_t* mapper_nest_explode_values_across_fields(lrec_t* pinrec, context_
 		if (istring_free_flags & FREE_ENTRY_KEY)
 			free(istring);
 		lrec_put(pinrec, new_key, mlr_strdup_or_die(piece), FREE_ENTRY_KEY|FREE_ENTRY_VALUE);
+		// xxx insert after if it doesn't already exit
 	}
-	lrec_remove(pinrec, pstate->field_name);
+	lrec_unlink_and_free(pinrec, pentry);
 	return sllv_single(pinrec);;
 }
 
diff --git a/c/todo.txt b/c/todo.txt
index af5ba6606..397cb454f 100644
--- a/c/todo.txt
+++ b/c/todo.txt
@@ -26,6 +26,7 @@ TOP-OF-LIST SUMMARY
 * valgrinds
 * xxxes
 * lrec get followed by put/remove: getext variant returning node for unlink, valpoke, or null == append to avoid double-searching.
+* dsls deps still not quite right?
 
 ================================================================
 * relcut material since 3.4.0: