Multiple tasks may be performed in a lumen of a living creature accessible via a path. One or more guides are optionally supplied. Optionally the guides communicate with a working channel of an endoscope. A tool may be conveyed along a guide through the working channel of the endoscope. For example a first tool may be conveyed to the lumen unblocking the working channel for a second tool. Optionally the second tool may subsequently be conveyed along a second guide. In some embodiments the guides may include thin channels in communication with the working channel via a longitudinal slit. Optionally the working channel may include a slit. For example large objects may be conveyed, along the working channel partially protruding from the longitudinal slit.
