Sakura and Shirou
To Sakura and Shirou's surprise and slight annoyance, the creatures reacted to her rain of arrows and his sword attacks by going into hiding, taking refuge in any convenient shelter they could find and remaining in place.
Realising that they had no real need to rush the battle, Sakura summoned up a few more of her shadow familiars, instructing them to seek out and destroy the hiding enemies, and then continued to hold her shadow bow, charging up arrows as before and waiting until she felt she could get a hit. With her current approach, the creatures were more-or-less pinned down, any which attempted to move out of cover would be instantly dispatched.
Shirou, meanwhile, realising that his swords were not currently necessary, switched back to his bow.
"Trace on!" he said, creating a low-level Noble Phantasm in his bow, one which would not produce a large explosion when broken.
Then, he took aim at one of the many enemies, intending to destroy their cover, and them along with it. Before he could do so, however, he saw Nanako come flying in, and immediately stopped himself, not sure that she would be able to withstand the blast.
"Nanako, move!" he shouted.
Sakura, however, continued her strategy, picking off any enemies which made any attempt to move out of their cover. After all, her arrows were unlikely to do much damage to the squirrel girl.