The infected creatures attack at night, but while Alice is walking round indoors in the dark it is clearly daylight outside.
The exterior view of Talbot's cabin at night has light shining from every window, yet inside a single dim table lamp seems to be the only illumination.
On the first night, Brienne looks for Matt carrying a bulky lantern. Two of the group then look for Brienne, also carrying identical bulky lanterns, but all three tents remain illuminated. Six such lanterns and three tents would have filled the backpacks of the entire group, even without food, cooking equipment, clothes, sleeping bags, first aid equipment or wash kits.
Brienne is infected before Jesse, but Jesse changes more quickly. When Brienne begins to show signs, though, Jules seems inexplicably reluctant to understand that she might be changing.
Alice finds Ketamine and says "This is horse tranquiliser". As a medical student she would be aware of its potential misuse as a narcotic, particularly when it is right next to handcuffs and shackles.
Talbot identifies three people infected by a virus. Alice identifies two more, then calculates the total affected as three.
Of the medical students, Alice is the one who wants to become an epidemiologist. This makes it harder to understand why she would be the last to grasp how the infection is spread.
When defending a building at night, it makes no sense to leave lights on inside. This allows attackers to see victims, but hides their own actions. It would make more sense to move all available lights outside, destroying the attackers' night vision and hiding those people inside.
When the group are first seen hiking, they appear to be following a mapped trail. This involves walking along a fallen tree trunk. Paths on maps tend to be there for several years, while fallen trees rot and become unsafe. Unless the tree had fallen exactly along the course of the trail, it is almost unthinkable that it would form part of the route.