Give your readers a way out! Unless you're designing a nefarious maze to trap unsuspecting super-spies on your Island of Doom, you don't want to leave people without a way out. If someone is relying on a keyboard or keyboard emulator navigate your website (as described in WCAG 2.1.1), make sure you avoid creating "keyboard traps"
A keyboard trap is a situation in which someone utilizing a keyboard has navigated to a component or section of a website and then is unable to return to where they were or move focus elsewhere using unmodified arrow or tab keys.This issue is most commonly seen when a number of formats are cobbled together within a site and rendered by the use of plug-ins or embedded applications.
When putting together your webpage, take a second to tab through your site's content to make sure that no traps exist. If, however, you determine that a keyboard trap cannot be avoided on your site, then you should include instructions to users on that page about how to shift focus away from the "trap" section.