When Walter and Astrid walk down the hospital corridor after visiting the cafeteria, Walter uses both hands to carry a heavy tray loaded with pudding, fruit cocktails and other things. They encounter Broyles in the hallway; although Walter never visibly puts the tray down, he starts gesticulating with one hand. His other hand remains out of the shot; so, in theory, it could still be holding the tray, but his arm does not appear to be straining to hold anything as heavy as a fully loaded cafeteria tray.
People who were in their cars during the lightning strikes should not have been harmed. A car is a form of Faraday Cage which acts as a protection from lightning.
At approximately 8:38 Walter states that the phrase "God helps those who help themselves" was coined by Ben Franklin, and included in his "Poor Richard's Almanac". While Franklin have put it in his almanac, the statement originated with Theologian Algernon Sydney.
(at around 10 mins) When Walter flies a kite to attract lightning, "wind" blows his and Astrid's hair along with other items in very close proximity to them, yet neither the trees in the background or behind the kite nor anything else in the surrounding area move at all, nor is the kite properly constructed in a manner that would allow it to actually "fly" even if there was wind.