Walking into a shopkeeper tries to pay the bill

src/uhitm.c

@@ -478,6 +478,9 @@ do_attack(struct monst *mtmp)
             if (inshop || foo) {
                 char buf[BUFSZ];
 
+                if (!gc.context.travel && !gc.context.run)
+                    return ECMD_TIME | dopay();
+
                 if (mtmp->mtame) /* see 'additional considerations' above */
                     monflee(mtmp, rnd(6), FALSE, FALSE);
                 Strcpy(buf, y_monnam(mtmp));