Win 10 is supposed to disable wireless in Safe Mode with Networking as it does in Win 8.1 so you would normally Ethernet connect, but if it isn't practical to do that, you can still use wireless in that mode.
At the desktop press CTRL+ALT+DEL then click on your WiFi icon in the system tray and then on your SSID and then on Connect.
Click on Cancel and then you'll see a normal WiFi icon.