Any course member can edit a course wiki page and any group member can edit a group wiki page, unless you have disabled this function. You might choose to disable editing when it is time to grade the wiki pages. However, you can still edit student pages. All course members, including instructors, edit in the same way.
When a user is editing a wiki page, it is locked for a duration of 120 seconds to prevent others from editing the same page. Users are informed that another user is currently editing the page. The lock will expire in 120 seconds regardless of a user’s activity/inactivity. After 120 seconds, another user can start editing the page and a new 120 seconds lock is placed on the page.
You cannot edit the lock or amount of time.