[grobdriver]

Except for the “two of them” thing

Roger that.
A pressure cooker in a backpack without looking suspicious.... maybe.

A backpack big enough for two pressure cookers... nope.

Maybe multiple trips...

[AppyPappy]

Plus the culprit had to hang around long enough to not look suspicious dropping off a package in a crowd.

[cripplecreek]

Even a 6 quart pressure cooker would be a stretch for one backpack.

[libstripper]

Equally important, a seven quart pressure cooker. I have a seven quart crock pot that's about fifteen inches long by 8 wide, by nine or ten deep. That size pressure cooker is going to be at least ten inches in diameter. Filled wiith explosives and shrapnel it's also going to weigh a good deal.