Amanita, while defending the comatose Meredith, is firing at any incoming monsters that dare approach the rooftop. Using every poison-filled bullet she has, she makes sure she hits one while inflicting them with her toxins.
"There's so many," Amanita said, "I don't know how long I can hold them off... unless..."
She turned to Meredith and a spark ignited in her head. Since she has an ability to enhance other people's powers, Amanita wondered if she can distract the remaining monsters to a single location and, while empowered, can detonate a toxic explosion that might hopefully be instantly fatal. Although there are a few problems.
First, she needs to find a way to gather them into one spot, or get most their attention.
Second, where will she lead them? The town's already deserted, but because of how deadly her toxins are, especially when enhanced, she wouldn't risk in endangering her allies if the radius is too wide.
Amanita's already low on bullets and her poison-glossed skin won't do much against these brutes. After a few rounds, her ammunition are finally exhausted. Now's the time to initiate her plan.